Abstract

The importance of autonomic nervous activity for the pancreatic hormonal response to exercise in man was studied. 7 men ran at 58 of VO2 max (determined without administration of drugs) to exhaustion during alpha-adrenergic blockade with phentolamine (P), during parasympathetic blockade with atropine (A), or without drugs (C). At rest phentolamine increased the plasma concentrationsof both insulin and norepinephrine. During exercise norepinephrine concentrations increased and were in P experiments 3 times the concentrations in C ex- periments. Insulin always declined during exercise but in P experiments never decreased below basal levels. At identical times neither glucagon nor glucose differed significantly in the different expts. Thus during exercise alphaadrenergic blockade increasedinsulin concentrations but did not diminish the glucagon response. Nor was this response increased when alpha-receptor stimulation in P experiments was intensified by the particularly high catecholamineconcentrations. The concentrations of FFA, glycerol and lactate were highest in P experiments and identical an A and C experiments. These findings indicatethat during prolonged moderate exercise in man insulin secretion is depressed by stimulation of alpha-adrenergic receptors whereas glucagon secretion ist not influenced by adrenergic receptors. Stimulation of alpha-adrenergic receptors enhances lipolysis but neither lipolysis nor pancreatic hormonal secretion is influenced by cholinergic activity during exercise. Verf.-Referat